The purpose of this study is to investigate the effect of Docosahexaenoic Acid (DHA) upon vision in individuals with LCHADD. DHA is a naturally-occurring fat that our bodies normally synthesize from the fat in our diet. DHA plays an important role in vision and other body functions. We have recently discovered that some individuals with LCHADD are deficient in DHA in the blood. This will be a five-year study that will require annual visits to Oregon Health Sciences University, Portland, Oregon. The second objective of this study is to obtain skin cells and establish cell lines from individuals with LCHADD. These skin cell lines (called skin fibroblast lines) can be grown and used repeatedly for LCHADD-related research without having to obtain new skin cell samples from the individual with LCHADD. In this project, skin cell lines will be used to examine DHA metabolism and to determine what specific changes in the LCHAD gene cause LCHADD.